Apparatus for processing plastics material

ABSTRACT

Disclosed is a device and a method for processing plastic material with at least one receiving container, wherein at least one mixing and/or comminution tool, rotatable about a rotation axis, is arranged, for mixing and warming the plastic material, and with at least one conveyor for discharging the plastic material from the receiving container, with at least one screw rotating in a housing, where the conveyor is connected, at its material inlet side via an opening which is formed in a side wall of the receiving container, with the interior of the receiving container. An imaginary extension of the central longitudinal axis of the conveyor extends, against the conveyance direction of the conveyor, past the rotation axis of the receiving container, without intersecting this axis, where the longitudinal axis of the conveyor is offset by a separation relative to the radial ray of the receiving container on the discharge side.

This application is a U.S. National Phase under 35 USC 371 of PCTApplication No. PCT/AT2011/000180 filed Apr. 13, 2011, which claimspriority to the Austrian Application No. 600/2010, filed Apr. 14, 2010,the disclosures of which are incorporated by reference herein.

The invention relates to a device according to the preamble of claim 1.

Numerous devices are known from the state of the art that comprise areceiving container or cutter compactor for the comminution, heating,softening and processing of a plastic to be recycled, and an extruderconnected to such devices for melting the material prepared in this wayis also known. The purpose here is to obtain a finished product of thehighest possible quality level, usually in the form of a granulate.

Thus, in EP 123 177, for example, a device is described with a receivingcontainer and an extruder connected to it, where the plastic materialfed into the receiving container is comminuted by rotating thecomminution and mixing tools, and brought into a vortex circulation, andat the same time heated by the added energy. As a result, a mixtureforms with sufficiently good thermal homogeneity. After an appropriateresidence time, this mixture is discharged from the receiving containervia the screw extruder, and in the process plasticized or melted. Thescrew extruder is arranged here approximately at the height of thecomminution tools and secured radially on the receiving container. Inthis way, the softened plastic particles are actively pushed into theextruder by the mixing tools.

Moreover, numerous devices are also known from the state of the art inwhich the extruder is connected tangentially to the receiving container.

All these devices share the fact that the conveyance and rotationdirection of the mixing and comminution tools, and thus the direction inwhich the material particles circulate in the receiving container, andthe conveyance direction of the extruder, are substantially the same orin the same direction. This arrangement, which is selected intentionallyin this way, is based on the intention to tamp the material as much aspossible into the screw, or to force feed the latter. In the process,and in variants based on this arrangement, care is always taken toensure as high as possible a filling of the screw, and to produce areinforcement of the tamping effect. For example, it has also beenattempted to widen the draw-in area of the extruder to the shape of acone or to curve the comminution tools to the shape of a sickle, so thatthey can feed the softened material like a spatula into the screw.

For this purpose, for example, in WO 88/02684, a device is described inwhich the extruder screw was moved out of the radial position, andconnected with radial shift, but not tangentially, on the receivingcontainer. This lateral offset has the result that the force componentof the circumferential force exerted by the rotating tool, whichcomponent acts in the axial direction of the extruder screw, becomesgreater in comparison to an arrangement in which the screw axis isarranged radially on the receiving container. As a result of theinlet-side offset, the tamping effect is further strengthened, and theplastic material is conveyed or pushed even better into the extruder bythe rotating tool.

Such devices are definitely advantageous for some materials,particularly for drawn or very strong plastics as well as for hard,small-piece flakes.

However, it has been found in experiments that such devices surprisinglycannot be used as advantageously for all plastic materials to berecycled, and that, on the contrary, they can even present disadvantagesin some areas.

Thus, for example, in the case of materials with a low energy content,such as, for example, PET fibers or films, or in the case of materialswith an early sticky or softening point, such as, for example,polylactic acid (PLA), the effect that was observed again and again wasthat intentional tamping of the plastic material into the draw-in areaof the extruder under pressure leads to premature melting of thematerial. This results, on the one hand, in a reduction of theconveyance effect of the extruder or of the grooved bush due to thelower toothing of the material with the grooves. In addition, partialbackflow of this melt into the area of the cutter compactor or receivingcontainer can occur, which leads to the still unmolten flakes adheringto the melt, and as a result the melt is cooled again and solidifiespartially, and in this way a swelling-like structure or conglomeratemade partially of solidified melt and solid plastic particles forms. Theresult is that the draw-in area of the extruder becomes clogged, and themixing and comminution tools stick together. Subsequently, thethroughput of the extruder decreases, because the filling of the snakeis no longer sufficient. In addition, the mixing and comminution toolscan get stuck in the process. As a rule, the installation has to beswitched off in such cases, and cleaned completely.

In addition, problems occur with polymer materials that have alreadybeen heated nearly to their melting range in the cutter compactor. Ifthe grooved bush is overfilled in the process, the material melts, andthere is a reduction of drawing-in.

Problems also arise with the usually drawn, striped, fibrous materialsthat present a certain longitudinal extension and low thickness orstiffness, that is, for example, plastic films cut into strips. This isfirst and foremost the result of the oblong material becoming stuck onthe discharge-side end of the draw-in opening of the screw, where oneend of the strip extends into the receiving container, and the other endinto a draw-in area. Since the mixing tools and also the screw run inthe same direction, or apply the same conveyance direction component andpressure component on the material, both ends of the strips are exposedto traction and pressure in the same direction, and the strip can nolonger be detached. This in turn leads to an accumulation of thematerial in this area, to a narrowing of the cross section of thedraw-in opening, and to a worse drawing-in behavior and subsequently tothroughput reductions. In addition, the elevated feed pressure in thisarea can lead to melting, which in turn results in the occurrence of theproblems mentioned at the beginning.

Thus, the problem of the present invention is to provide a device bymeans of which the disadvantages mentioned at the beginning can beavoided, and by means of which even sensitive or stripe-shaped materialscan be drawn in by the screw without problem.

This problem is solved in a device of the type mentioned at thebeginning by the characterizing features of claim 1.

Here, it is provided that the imaginary extension of the centrallongitudinal axis of the conveyor or of the screw extends, against theconveyance direction of the conveyor, past the rotation axis of thereceiving container, without intersecting this axis. The longitudinalaxis of the conveyor is offset by a certain distance relative to theradial ray of the receiving container, which is in the same direction asor parallel to the longitudinal axis, on the discharge side, or in therotation or movement direction of the mixing and/or comminution toolthat moves past the opening, or of the plastic material that passes bythe opening. As a result, the conveyance direction of the mixing toolsand the conveyance direction of the extruder are no longer in the samedirection, as known in the state of the art, but they are at leastslightly in the opposite direction, which results in a reduction of thetamping effect mentioned at the beginning. Due to the intentionalreversal of the rotation direction of the mixing and comminution tools,in comparison to the previously known devices, the feed pressure withrespect to the draw-in position decreases, and the risk of overfillingis diminished. In this way, no excess material is tamped or spatulaapplied at excessive pressure into the draw-in area of the extruder; onthe contrary, excessive material even tends to be removed from there, sothat, although sufficient material is always present in the draw-inarea, it is exposed to near zero pressure or only to a low pressure. Inthis way, the extruder screw can be filled sufficiently, and it canalways draw in sufficient material, without local pressure peaksoccurring, at which the material could melt.

In this way, melting of the material in the area of the extruder draw-inarea is prevented, resulting in an elevation of the operatingefficiency, an increase in the length of the maintenance interval, and ashortening of downtime due to possible repairs and cleaning measures.

Due to the reduction of the feed pressure, the pressure on any slidersthat close the draw-in opening is also decreased, where the sliders canbe used in a known way to regulate the filling degree of the screw. Thesliders consequently react clearly more sensitively, and the fillingdegree of the screw can be adjusted even more precisely. In the case ofheavier materials in particular, such as, for example, materials to beground that are made of high-density polyethyelene (HDPE) or PET, theoptimal operating point of the installation can thus be found moreeasily.

Moreover, it was found to be surprisingly advantageous that materialswhich were softened already to near melting are drawn in better duringthe operation in opposite directions according to the invention. Inparticular, if the material is already in a pasty or softened state,then the screw cuts itself the material out of the pasty ring. In thecase of a rotation direction in the conveyance direction of the extruderscrew, this ring would instead tend to be moved along, and no scrapingoff could occur, which would result in a reduction of the drawing-in.This is prevented by the reversal of the rotation direction according tothe invention.

In addition, when processing the above-described striped or fibrousmaterials, stuck materials or accumulations that formed can be detachedmore easily, or they do not form at all in the first place, because, onthe edge of the opening, which edge is located in the rotation directionof the mixing tools on the discharge side or downstream, the directionvector of the mixing tools and the direction vector of the extruder canpoint in almost opposite or at least slightly opposite directions, as aresult of which an oblong strip cannot bend around and become stuck tothis edge, rather it is pulled along again by the mixing vortex in thereceiving container.

Overall, as a result of the arrangement according to the invention, thedrawing-in behavior is improved, and the throughput is increased. Theoverall system of cutter compactor and extruder is more stable as aresult.

Additional advantageous embodiments of the invention are described inthe following dependent claims.

According to an advantageous variant of the invention, it is providedthat the conveyor is arranged in such a way on the receiving containerthat the scalar product of the direction vector which is oriented so itis tangential with respect to the circle of rotation of the mixingand/or comminution tool, or with respect to the plastic material thatpasses by the opening, and normal with respect to the radial ray of thereceiving container, and which points in the rotation or movementdirection of the mixing and/or comminution tool, and the directionvector of the conveyance direction of the conveyor, is zero or negativeat each individual point or in the entire area of the opening, or ateach individual point or in the entire area immediately before theopening. In this way, the advantages mentioned at the beginning areachieved. Moreover, the crucial factor here is in particular not thespatial arrangement of the mixing tools and of the extruder with respectto each other; for example, it is not necessary for the mixing tools andthe extruder screw respectively the opening to be necessarily in acommon plane, and the rotation axis does not need to be oriented so itis normal with respect to the bottom surface or the longitudinal axis ofthe extruder.

An additional advantageous embodiment is obtained if the directionvector of the mixing and/or comminution tool forms an angle greater thanor equal to 90°, and smaller than or equal to 180°, with the directionvector of the conveyance direction of the conveyor, where the angle atthe intersection of the two direction vectors is measured at theupstream margin of the opening, with respect to the rotation or movementdirection, particularly at the point that is located farthest upstreamon this margin or the opening. As a result, the angular range describedis the one in which the extruder must be arranged on the receivingcontainer, in order to achieve the advantageous effects. Here, in theentire area of the opening or at each individual point of the opening,there is an orientation of the forces acting on the material that is atleast slightly in opposite directions, or, in the extreme case, apressure-neutral transverse orientation. At no point of the opening isthe scalar product of the direction vectors of the mixing tools and ofthe conveyor screw positive; thus, an excessively large tamping effectdoes not occur even in a partial area of the opening.

In an additional advantageous embodiment of the invention, it isprovided that the direction vector of the rotation or movementdirection, and the direction vector of the conveyance direction enclosean angle of 170-180°, measured at the intersection of the two directionvectors in the middle of the opening. Such an arrangement is applicable,for example, if the extruder is arranged tangentially on the cuttercompactor.

In order to ensure that no excessive tamping effect occurs, it isadvantageous to provide that the separation is greater than or equal tohalf of the inner diameter of the housing of the conveyor or of thescrew.

Moreover, in this sense, it can be advantageous to choose a size for theseparation which is greater than or equal to 7%, or more advantageouslygreater than or equal to 20%, of the radius of the receiving container.

In the case of radially offset, but not tangentially arranged,extruders, it is advantageous to provide that the imaginary extension ofthe longitudinal axis of the conveyor, against the conveyance direction,penetrates the internal space of the receiving container at least insections.

In this connection, it is advantageous if it is provided that theopening is arranged immediately before the rear—in the conveyancedirection—end face of the screw.

In the case of extruders with an extended draw-in area or a grooved bushor an enlarged pocket, it can be advantageous if the separation isgreater than or equal to the radius of the receiving container. Thisapplies particularly to cases where the conveyor is connectedtangentially to the receiving container.

The reversal of the rotation direction of the tools rotating in thecontainer is in no way arbitrary, and one cannot—in the known devices orin the device according to the invention—allow the mixing tools torotate in opposite direction without problem; this cannot be doneparticularly since the mixing and comminution tools are arrangedsomewhat asymmetrically or with directional orientation such that theycan act on only one side or in only one direction. If one were to rotatesuch an apparatus in the wrong direction, then a good mixing vortexwould not form, and there would not be sufficient comminution or warmingof the material. Consequently, each cutter compactor has a fixedpredetermined rotation direction.

In this connection it is particularly advantageous if it is providedthat the front areas or front edges of the mixing and/or comminutiontools, which act on the plastic material, and point in the rotation ormovement direction, are designed, curved, placed or arrangeddifferently, in comparison to the rear—in the rotation or movementdirection—or lagging areas.

Here, an advantageous arrangement provides for arranging, on the mixingand/or comminution tool, tools and/or knives that act in the rotation ormovement direction on the plastic material, with comminution effect andoptionally also warming effect, where the knives are preferablyarranged, in particular parallel to the bottom surface, on a carrierdisk arranged so it can rotate.

In principle, the effects mentioned at the beginning are relevant notonly with compressive screw extruders, but also with noncompressiveconveyor screws. Here too, local excess feeding should be prevented.

In an additional advantageous embodiment, it is provided that thereceiving container is substantially cylindrical, with a flat bottomsurface and a cylinder barrel-shaped side wall that is vertical withrespect to the bottom surface.

Moreover, in a simple construction, the rotation axis coincides with thecentral middle axis of the receiving container.

In an additional advantageous embodiment, it is provided that therotation axis or the central middle axis is oriented so it is verticalor normal with respect to the bottom surface.

As a result of these special geometries, the drawing-in behavior isoptimized in a device of stable construction and simple structure.

In this connection, it is also advantageous to provide that thelowermost mixing and/or comminution tool and/or the opening are arrangedat a small separation from the bottom surface, particularly in the areaof the lowermost quarter of the height of the receiving container.

Moreover, it is advantageous for the processing if the outer edges ofthe mixing and/or comminution tool extend close to the side wall.

According to the invention, a method for operating such a device is alsoprovided.

Here, on the one hand, the rotation and/or movement direction of themixing and/or comminution tool must be set in such a way, and the mixingand/or comminution tool must be designed or the knives arranged in sucha way, and the mixing and/or comminution tool must be arranged andoriented in such a way in the receiving container that a proper mixingand processing of the polymer material occurs. Here, a correct mixingvortex must form, and the mixing and/or comminution tool must be able toact correctly on the material, that is, with mixing, warming, andoptionally comminuting effect.

Moreover, one must ensure that the rotation or movement direction of themixing and/or comminution tool is set in such a way that the imaginaryextension of the central longitudinal axis of the conveyor or of thescrew is moved, against the conveyance direction of the conveyor, pastthe rotation axis of the receiving container without intersecting it,where the longitudinal axis of the conveyor is offset by a separationrelative to the radial ray of the receiving container, which is in thesame direction or parallel with respect to the longitudinal axis, on thedischarge side or in the rotation or movement direction of the mixingand/or comminution tool which moves past the opening or of the plasticmaterial which is moved past the opening. As a result, theabove-mentioned advantageous effects are achieved.

This method can be developed further using the characteristics of thedependent claims regarding the device.

Additional advantages and embodiments of the invention can be obtainedfrom the description and the associated drawings.

The invention is represented diagrammatically with the help ofembodiment examples in the drawings, and it is described below, based onan example, in reference to the drawings.

FIG. 1 shows a vertical section through a device according to theinvention.

FIG. 2 shows a horizontal section through a slightly modified embodimentin the direction of the arrow II of FIG. 1.

FIG. 3 shows an additional embodiment with a larger radial offset.

FIG. 4 shows an additional embodiment with an approximately tangentiallyconnected extruder.

FIG. 5 shows an additional embodiment with an approximately tangentiallyconnected extruder and curved mixing tools.

FIG. 6 shows a device known from the state of the art.

The advantageous device for processing or recycling plastic material,represented in FIG. 1, shows a receiving container or cutter compactor1, which is known sufficiently from the state of the art, for example,from EP 123 771. The receiving container 1 is cylindrical with a flatbottom surface 2 and a cylinder barrel-shaped side wall 9 which isoriented vertically with respect to the bottom surface.

At a small separation from the bottom surface 2, at approximately10-20%, optionally less, of the height of the side wall 9—measured fromthe bottom surface 2 to the uppermost margin of the side wall 9—a flatcarrier disk 13 is arranged, which is oriented parallel to the bottomsurface 2, and which can be rotated about a central rotation axis 10,which is at the same time the central middle axis of the receivingcontainer 1, in the rotation or movement direction 12 marked by anarrow. The carrier disk 13 is driven by a motor 21 which is locatedbeneath the receiving container 1. On the carrier disk 13, knives 14 arearranged, which, together with the carrier disk 13, form the mixingand/or comminution tool 3.

As shown diagrammatically in FIG. 2, the knives 14 are not arrangedregularly on the carrier disk 13, rather they are designed, placed orarranged in a special way, on the front edge pointing in the rotation ormovement direction 12, in order to be able to act on the plasticmaterial. As a result, a mixing vortex forms in the receiving container1, where the material is moved about turbulently, from top to bottom andalso in the rotation direction 12. Such a device can consequently beoperated only in the predetermined rotation or movement direction 12,because of the special arrangement of the mixing and comminution tools 3or of the knives 14, and the rotation direction 12 cannot be reversedwithout problem or without modifications.

Moreover, to improve the supplying of material to the opening 8,deflectors can be mounted on the periphery of the container or on theside wall 9.

The mixing and comminution tools 3 represented in FIGS. 3 and 4 are alsorepresented only diagrammatically. The knives 14 are arranged on thefront edges 22 acting on the material (FIG. 3).

Theoretically, it is also possible for the mixing and comminution tools3 to present a regular or symmetric structure. However, in that case aswell, the rotation or movement direction 12 cannot be reversed at will;rather they are predetermined by the motor or by special geometries ofthe receiving container 1 and/or of the draw-in area of the extruder 5.

For comparison, a device known from the state of the art is shown inFIG. 6. It has two levels of mixing and comminution tools 3 which rotatein the direction of the arrow 12, that is not in the direction accordingto the invention. In the vicinity of the bottom 2, rotating knives 14which have a radial or straight orientation are arranged in the lowerlevel. In the overlying level, on a carrier disk 13, knives 14 withfront cutting edges 22 are arranged, which are curved or angled againstthe rotation direction 12. During operation, this results in the wantedand necessary mixing vortex, during the rotation of the tools. A simplechange of the rotation direction 12 is thus not possible precisely here.

At the height of the, in the present case single, comminution and mixingtool 3, in the side wall 9 of the receiving container 1, an opening orinlet or feed opening 8 is formed, to which the housing 16 of a conveyor5 is connected. A compressive extruder screw 6 is mounted in the housing16 so it can rotate, and it can be driven by a shaft of the motor 21.

The outer edges of the mixing and comminution tools 3 extend relativelyclose, approximately 5% of the radius, to the side wall 9. The screw 6and the housing 16 of the extruder 5, in the area of the opening 8, areadapted to the contour of the inner wall of the receiving container 1,and set back. No part of the extruder 5 extends into the internal spaceof the receiving container 1. The mixing and/or comminution tools 3 orthe knives 14 are located at approximately the same height or level asthe central longitudinal axis 15 of the extruder 5. However, theoutermost ends of the knives 14 are at a sufficient separation from theend face 7 of the extruder 5.

In the examples represented in the figures, the extruder is always acompressive single shaft or single screw extruder. However,alternatively, it is also possible to provide double or multiple shaftextruders, or to install noncompressive conveyor screws.

During operation, the plastic material to be processed, usually in theform of plastic waste, bottles or films, is introduced via an openfeeding funnel into the receiving container 1. Alternatively, it can beprovided that the receiving container 1 is closed, and can be evacuatedat least to a technical vacuum. The plastic material introduced iscomminuted by the rotating mixing and comminution tools 3, mixed, and inthe process warmed and softened, but not melted, by the added mechanicalfrictional energy. After a certain residence time in the receivingcontainer 1, the softened, but not molten material, is introduced intothe draw-in area of the extruder 5 or into the opening 8, and there itis gripped by the screw 6, and subsequently melted.

In FIG. 2, a cross section through an embodiment that is very similar toFIG. 1 is represented, at the level of the extruder screw 6. One can seethat the rotation axis 10 as well as the central middle axis of thereceiving container 1 coincide, and that the cross section of thereceiving container 1 is circular. Alternatively, elliptical shapes oran eccentric arrangement of the rotation axis 10 would also be possible.

The extruder 5 is a conventional extruder which in itself is known, inwhich, in a first zone, the softened plastic material is melted,subsequently compression occurs, and then the melt exits on the oppositeside. The extruder 5 conveys in the direction of the arrow 17. Thehousing 16 as well as the screw 6 are slightly widened conically on thedischarge side in the draw-in area. The opening 8 is arrangedimmediately before the rear end face 7 of the screw 6.

In the embodiment according to FIG. 2, the extruder or conveyor 5 is notconnected radially to the receiving container 1, but offset on thedischarge side. The backward imaginary extension of the centrallongitudinal axis 15 of the conveyor 5 or of the screw 6, against theconveyance direction 17 of the conveyor 5, extends on the left alongsidepast the rotation axis 10, without intersecting this axis. Thelongitudinal axis 15 is here offset by a separation 18 in the rotationor movement direction 12, relative to the radial ray 11 of the receivingcontainer 1, which is in the same direction as or parallel to thelongitudinal axis. The backward imaginary extension of the longitudinalaxis 15 of the conveyor 5 penetrates the internal space of the receivingcontainer 1.

The separation 18 in FIG. 2 corresponds to approximately 15-20% of theradius of the receiving container 1. In the present case, the separation18 corresponds approximately to half the inner diameter of the housing16, and thus represents a first limit case or extreme value withsmallest possible offset or separation 18, in which the rotation ormovement direction 12 of the mixing and/or comminution tools 3 isoriented at least slightly in the opposite direction of the conveyancedirection 17 of the conveyor 5, in fact over the entire surface of theopening 8. The terms “directed opposite” or “in the opposite direction”here denotes any orientation of the vectors with respect to each otherwhich does not result in an acute angle, as explained in detail below.

In other words, the scalar product of a direction vector 19 of therotation direction 12, which is oriented so it is tangential to thecircle of rotation of the mixing and/or comminution tool 3 or tangentialwith respect to the plastic material that passes by the opening 8, andwhich points in the rotation or movement direction 12 of the mixingand/or comminution tools 3, and a direction vector 17 of the conveyancedirection of the conveyor 5, which extends in the conveyance directionparallel to the central longitudinal axis 15, at each individual pointof the opening 8 or in the area immediately before the opening 8 iseverywhere zero or negative, but nowhere positive.

In FIG. 2, the scalar product is exactly zero at the farthest upstreamlimit-value point 20 which is located on the farthest upstream margin ofthe opening 8. The angle α between the direction vector 17 of theconveyance direction and the direction vector 19, measured at point 20of FIG. 2, is exactly 90°. If one moves along the opening 8 towards theleft, that is further in the rotation direction 12, then the angle αbecomes increasingly larger, forming an obtuse angle, and at the sametime the scalar product becomes negative. However, at no point or areaof the opening 8 is the scalar product positive, or the angle α smallerthan 90°. As a result, local excess feeding cannot occur even in apartial area of the opening 8, or a damaging excess tamping effectcannot occur in any area of the opening 8. Thus, there is also nodecisive difference compared to a radial arrangement, because point 20or the edge 20, in the case of a radial arrangement of the extruder 5,would present an angle α<90°, and those areas of the opening 8 that arelocated to the right alongside the radial ray 11, or upstream or on theinlet side, would have a positive scalar product. As a result, locallymolten plastic material can accumulate in these areas.

In FIG. 3, an alternative embodiment is represented, in which theconveyor 5, on the discharge side, is offset even further radially thanin FIG. 2, and the separation 18 is correspondingly larger. The angle αmeasured at point 20 is approximately 145°, which results in the tampingeffect being further reduced compared to the device of FIG. 2, which canbe even more advantageous for certain sensitive polymers. The margin ofthe housing 16, on the right side viewed from the receiving container 1,is installed tangentially on the receiving container 1, where, incontrast to FIG. 2, no dull transition edge is formed on which thematerial could be caught.

In FIG. 4, an additional alternative embodiment is represented, in whichthe extruder 5 is connected tangentially on the receiver container 1.The angle α, measured at point 20 between the direction vector 19 andthe direction vector 17 is, approximately 160°, which is near maximal.In the present case, the backward imaginary extension of thelongitudinal axis 15 of the conveyor 5, no longer penetrates theinternal space of the receiving container 1, rather it extends alongsidepast it. The separation 18 is enlarged further and it is even greaterthan the radius of the receiving container 1. The extruder 5 is thusoffset towards the exterior in a pocket-like broadening, or the draw-inarea is slightly deeper. An angle β between the direction vector 19 andthe direction vector 17, which is not included in the drawing of FIG. 4,and which is measured in the middle or in the center of the opening 8,is approximately 175°. The device according to FIG. 4 represents thesecond limit case or extreme value with the relatively smallest tampingeffect. In such an arrangement, a particularly pressure-less feeding ispossible, and such a device is advantageous particularly for sensitivematerials that are processed close to the melting area, or for materialin the form of long strips.

FIG. 5 shows an additional alternative embodiment with tangentiallyconnected extruder 5, and with knives or tools 14 on the carrier disk 13that are curved and mutually offset, where the front cutting edges 22,viewed in the rotation direction 12, effect a comminution and warming ofthe material.

The invention claimed is:
 1. A device for treating plastic materials,comprising at least one receiving container (1) in which at least onemixing and/or comminution tool (3) which is rotatable around arotational axis (10) is disposed for mixing and heating and, optionally,cutting and/or softening said plastic materials, wherein the at leastone mixing and/or comminution tool (3) has an extreme point located atthe greatest radial distance from the rotational axis (10) and whereinthe extreme point located at the greatest radial distance from therotational axis (10) defines a bounding circle when the at least onemixing and/or comminution tool (3) is rotated about the rotational axis(10), and at least one conveyor (5) for transporting the plasticmaterials out of the receiving container (1), said conveyor (5) havingat least one screw (6) rotating in a housing (16) and, said conveyor (5)being at its material input side, connected to the interior of thereceiving container (1) via an opening (8) formed in a lateral wall (9)of said receiving container (1) in order to supply or feed the materialinto said receiving container (1), said opening (8) being disposed atthe height of the mixing and/or comminution tool (3), wherein a portionof the central longitudinal axis (15) of the conveyor (5) and the screw(6) in the direction opposite the conveying direction (17) of theconveyor (5) passes the rotational axis (10) of the receiving container(1) without intersecting it, said longitudinal axis (15) of the conveyor(5) and the screw (6) being offset in the rotational and movingdirection (12) of the mixing and/or comminution tool (3), which isrotating past the opening (8), and of the plastic materials, which aretransported past the opening (8), at a discharge side by a distance (18)from a radial line (11) of the container (1), which is parallel to thelongitudinal axis (15) and, in the conveying direction (17) of theconveyor (5), extends outwards from the rotational axis (10) of saidmixing and/or comminution (3) tool, wherein the screw (6) is outside ofthe bounding circle.
 2. A device according to claim 1, characterized inthat the conveyor (5) is arranged in such a way on the receivingcontainer (1) that a scalar product of a direction vector (19) of themixing and/or comminution tool (3) which is oriented so it is tangentialwith respect to the circle of rotation of the mixing and/or comminutiontool (3), or with respect to plastic material that is moved past theopening (8), and normal with respect to a radial ray (11) of thereceiving container (1), and which points in the rotation or movementdirection (12) of the mixing and/or comminution tool (3), and adirection vector (17) of the conveyance direction of the conveyor (5),is zero or negative at each individual point of the opening (8).
 3. Adevice according to claim 2, characterized in that the direction vector(19) of the mixing and/or comminution tool (3) and the direction vector(17) of the conveyance direction of the conveyor (5) form an angle (α)greater than or equal to 90°, and smaller than or equal to 180°,measured at the intersection of the two direction vectors (17, 19), at aportion of the opening (8), which is upstream with respect to therotation or movement direction (12).
 4. A device according to claim 2,characterized in that the direction vector (19) of the mixing and/orcomminution tool (3) and of the rotation or movement direction (12), andthe direction vector (17) of the conveyance direction enclose an angle(β) of 170-180°, measured at the intersection of the two directionvectors (17, 19) in the middle of the opening (8).
 5. A device accordingto claim 1, characterized in that a separation (18) is greater than orequal to half the inner diameter of the housing (16) of the conveyor (5)or of the screw (6), and/or ≧7%, preferably ≧20%, of the radius of thereceiving container (1).
 6. A device according to claim 1, characterizedin that the portion of the longitudinal axis (15) of the conveyor (5)and the screw (6) in the direction opposite the conveying direction (17)of the conveyor (5), penetrates the internal space of the receivingcontainer (1) at least in sections.
 7. A device according to claim 1,characterized in that the opening (8) is arranged immediately before arear end face (7), in the conveyance direction (17), of the screw (6).8. A device according to claim 1, characterized in that a separation(18) is greater than or equal to the radius of the receiving container(1).
 9. A device according to claim 1, characterized in that theconveyor (5) is connected tangentially on the receiving container (1).10. A device according to claim 1, characterized in that the mixingand/or comminution tool (3) comprises tools and/or knives (14) that act,in the rotation or movement direction (12), on the plastic material,with comminution effect and optionally also warming effect, where thetools or knives (14) are arranged preferably on a rotatable carrier disk(13) that is arranged parallel to a bottom surface (12).
 11. A deviceaccording to claim 1, characterized in that the conveyor (5) is anoncompressive screw conveyor or a compressive screw conveyor.
 12. Adevice according to claim 1, characterized in that the receivingcontainer (1) is substantially cylindrical, with a flat bottom surface(2) and a cylinder barrel-shaped side wall (9) that is vertical withrespect to the bottom surface, and/or the rotation axis (12) coincideswith the central middle axis of the receiving container (1), and/or therotation axis (12) or the central middle axis present an orientationthat is vertical or normal with respect to the bottom surface (2).
 13. Adevice according to claim 1, characterized in that the lowermost mixingand/or comminution tool (3) and/or the opening (8) are arranged at asmall separation from the bottom surface (2), wherein arranging thelowermost mixing and/or comminution tool (3) and/or the opening (8) at asmall separation from the bottom surface (2) places the lowermost mixingand/or comminution tool (3) in the area of a lowermost quarter of theheight of the receiving container (1).
 14. A device according to, claim1, characterized in that the outer edges of the mixing and/orcomminution tools (3) extend close to the side wall (9).
 15. The deviceof claim 3, wherein the angle (α) is measured at the point (20) that islocated farthest upstream on the opening (8).